Dynamics simulation on interaction of intense laser pulses with atomic clusters

Under classical particle dynamics, the interaction process betweenintense femtosecond laser pulses and icosahedral noble-gas atomicclusters was studied. Our calculated results show that ionizationproceeds mainly through tunnel ionization in the combined field fromions, electrons and laser, rather than the electron-impactionization. With increasing cluster size, the average andmaximum kinetic energy of the product ion increases. According to ourcalculation, the expansion process of the clusters after laserirradiation is dominated by Coulomb explosion and the expansionscale increases with increasing cluster size. The dependence ofaverage kinetic energy and average charge state of the product ions onlaser wavelength is also presented and discussed. The dependence ofaverage kinetic energy on the number of atoms inside the cluster wasstudied and compared with the experimental data. Our results agreewith the experimental results reasonably well.